I wanted a bit of texture and some color variation so a quick&dirty solution was Joanne Fabrics fleece. They offer a color I like to call "desert floor".
The fleece laid well on this hard-shell mountain. It is a bit simple and crude but I like the effect. You can see in this pic (bottom right) that I had to "cut&paste" an area of fleece after doing some "landscaping" on the hard-shell underneath:
If I choose to keep this "ground cover" I'll apply grass and shrubs and that will conceal all the seams and tone down the variation between dark brown and light tan.